This invention is directed to hand tools for use in the insertion of conductors in solderless connectors and especially to tools for use in the installation of individual conductors of communications cables in connectors extending from terminal blocks. More particularly, the present invention relates to the establishment of solderless connections between electrical conductors, particularly insulated conductors, and closely spaced connectors in communications systems.
The present invention is particularly well suited for use with the multiple electrical connector of U.S. Pat. No. 4,381,880, which is assigned to the assignee of the present invention and is incorporated herein by reference.
The present invention has been found to be particularly useful in the communications field and especially in the telephonic art. It is common, in the installation of a telephone system, for multiple conductor telephone cables to be terminated at a mounting block which has a plurality of solderless connectors extending outwardly therefrom. The cable conductors are inserted in connectors, typically between a pair of opposed fingers, in such a manner as to establish electrical connection without resort to bonding techniques such as soldering. The connectors, and particularly the opposed fingers or other elements between which each of the cable conductors is inserted, are designed such that any insulation on the conductor is removed therefrom as the conductor is forced between the opposing elements of the connector.
In the prior art, wherein the opposing contact elements of the connectors were formed from flat stock, wire installing tools of the type disclosed in U.S. Pat. No. 4,194,256 have been designed for use by the technician. These prior wire installing tools, however, cannot be employed in the insertion of electrical conductors in the connectors of a multiple connector assembly of the type disclosed in referenced U.S. Pat. No. 4,381,880. To be more specific, referring to prior art "flat" connectors of the type known in the art as the "66 Type", which are shown in U.S. Pat. No. 3,112,147, the installing tool must be provided with an internal cavity which functions to hold the fingers or beams of the connector together as a conductor is forced therebetween. If too much spreading of the connector fingers is permitted, the fingers (typically being comprised of copper alloys), will undergo cold flow in the base regions of the fingers and there will be insufficient force applied to the conductor to insure its permanent capture between the fingers. The connectors of U.S. Pat. Nos. 4,381,880 and 4,425,019 are defined by high strength coil segments. As a conductor is forced between a pair of these opposed coil segments, the forces imposed on the outermost portions of the connector are high while those at the bottom of the cooperating elements or segments remain low. This is precisely the opposite to what occurs in a "66 Type" connector. Accordingly, there is no danger of cold flow of the copper wire which defines the connector segments. Thus, a tool cavity to prevent excessive spreading of the fingers of the connector is not required.
An attempt at providing a suitable installing tool for connectors of the type described in U.S. Pat. No. 4,381,880 was made in U.S. Pat. No. 4,408,391, assigned to the assignee, hereof, all of the contents of which are incorporated herein by reference. While suitable for its intended purpose, the installation tool of U.S. Pat. No. 4,408,391 suffers from certain defiencies and shortcomings. Chief among these problems is a lack of structural strength in the blade. Blade portions 20 and 20' of the stem portion 12 of the prior art tool have a much narrower width as compared to the center body portion 18. As a result, it has been found that blade portions 20, 20' may fracture and break during repeated usage. Accordingly, the prior art installation tool of U.S. Pat. No. 4,408,391 may become undesirably expensive in terms of labor, repair and replacement costs.